This invention relates to containers for pourable materials, and in particular to a closure for such a container formed to firmly retain the contents yet readily openable by slide means to permit pouring of the contents or any portion thereof from container.
Immense quantities of pourable consumer products, such as detergent granules, powders or liquids, foods such as sugars, macaroni and other pastas, cereals including prepared breakfast foods and many other items, are produced, packaged, marketed and consumed every day. A common package is a cardboard box having a top with some provision for opening so that the box can be tipped and the contents poured out for use. Specific examples are granular detergents packed in cardboard boxes having a partially cut out area in or near the top which can be forced in by a finger or thumb to provide an opening, and prepared breakfast foods that have an air tight inner bag and a box closed by flaps that are glued together. The latter can be more or less closed by folding over the top of the opened bag and then bringing together the flaps which are usually provided with a tongue and slit for holding them together. While huge quantities of such packages are sold, most are quite deficient in that once they are opened, they cannot be satisfactory closed. The granular detergents can spill from the opening and the flaps of cereal boxes are frequently torn in the initial opening of the boxes, preventing proper closure. Since similar products sold by different manufacturers are highly competitive, cost is definitely a limiting factor insofar as package design and construction are concerned, and since the packages normally are thrown away when the contents have been used.